Showing papers on "Fourier transform infrared spectroscopy published in 1983"
TL;DR: The data appear to present the first direct spectroscopic evidence of turns in a native protein, as seen in Fourier transform infrared spectra obtained in deuterium oxide solution from 1350 to 1800 cm-1.
485 citations
TL;DR: In this paper, the authors used long-path Fourier transform infrared spectroscopy to follow the chemical changes in irradiated HONO, CO, SO2, NOx, O2N2 gaseous mixtures.
339 citations
TL;DR: The real-time optical Fourier transformer is shown to be realizable by using dispersive single-mode fibers and chirping lasers.
Abstract: The general concept of temporal Fourier transformation in dispersive media is analyzed. The real-time optical Fourier transformer is shown to be realizable by using dispersive single-mode fibers and chirping lasers.
176 citations
TL;DR: In this article, the Fourier transform infrared (FTIR) spectroscopy was used to determine the type and amount of surface functional groups in carbon black, and the results showed that carboxylic or quinone groups in the amount of ~0.1-1.8 meq/g were detected.
170 citations
TL;DR: In this article, subtractively normalized interfacial Fourier transform infrared spectroscopy applied to the in situ study of the electrode-electrolyte solution interphase is presented, which is used to obtain difference infrared spectra of electrogenerated intermediates and species adsorbed at the electrode surface.
130 citations
TL;DR: Events occurring during thermally induced fibrillogenesis process can be monitored, in aqueous media and in real time, by Fourier transform infrared spectroscopic techniques.
Abstract: When a solution of collagen molecules, at neutral pH and moderate ionic strength, is warmed from 4 degrees to 30 degrees C, a spontaneous self-assembly process takes place in which native-type collagen fibers are produced. Events occurring during thermally induced fibrillogenesis process can be monitored, in aqueous media and in real time, by Fourier transform infrared spectroscopic techniques. Tentative assignments of observed spectral bands are given.
96 citations
TL;DR: Glycophorin from the human erythrocyte membrane has been isolated in pure form and reconstituted into large unilamellar vesicles comprised of binary mixtures of DPPC and chain perdeuterated 1,2-dimyristoyl-3-sn-phosphatidylcholine (DMPC-d54).
Abstract: Glycophorin from the human erythrocyte membrane has been isolated in pure form and reconstituted into large unilamellar vesicles comprised of binary mixtures of 1,2-dipalmitoyl-3-sn-phosphatidylcholine (DPPC) and chain perdeuterated 1,2-dimyristoyl-3-sn-phosphatidylcholine (DMPC-d54) The effect of temperature and protein on lipid structure and mixing was monitored by using Fourier transform infrared spectroscopy; deuteration of one of the components of the mixture permits observation of the protein interaction with each lipid species The melting curves were analyzed by assuming that each lipid chain can exist in one of two physical states (ie, gel or liquid crystalline), characterized by a temperature-dependent Lorentzian distribution for the line shape of the C-H or C-D stretching vibrations The fraction of each lipid component melted at temperatures within the two-phase region of the phase diagram was calculated and approximate phase diagrams were constructed Addition of protein lowers the liquidus line of the phase diagram while leaving the solidus line essentially unchanged No lipid phase separation is observed The effect of protein is more pronounced on the DPPC component than on the DMPC-d54 The former is significantly more disordered and/or fluidized at all lipid mole fractions in the ternary system than in the binary phospholipid mixture
81 citations
TL;DR: In this article, the Fourier transform infrared (FTIR) method was used in the uv (300-400-nm) photolysis of mixtures containing CH3SCH3, C2H5ONO, and NO in ppm concentrations in 700 torr of O2-N2 diluent.
Abstract: Product studies were made using the Fourier transform infrared method in the uv (300–400-nm) photolysis of mixtures containing CH3SCH3, C2H5ONO, and NO in ppm concentrations in 700 torr of O2–N2 diluent. Methyl thionitrite, CH3SNO, arising from the reaction CH3S + NO, was detected as an intermediate product. In addition, the yields of the major sulfur-containing products SO2 and CH3SO3H coincided with those of the oxidation of the CH3S radicals generated directly by the photodissociation of CH3SNO. The formation of CH3S in the HO-initiated oxidation of CH3SCH3 in the presence of NO suggests a reaction scheme involving the H-abstraction reaction HO + CH3SCH3 CH3SCH2 + H2O as the primary step.
73 citations
TL;DR: In this article, the reaction of OH radicals with CS2 has been investigated by the application of Fourier transform infrared spectroscopy using both photolytic and nonphotolytic competitive techniques in a 420-L reaction chamber at different pressures over the temperature range of 264-293 K.
Abstract: The reaction of OH radicals with CS2 has been investigated by the application of Fourier transform infrared spectroscopy using both photolytic and nonphotolytic competitive techniques in a 420-L reaction chamber at different pressures over the temperature range of 264–293 K. The measured effective rate constant was found to be dependent on total pressure, temperature, and the mole fraction of O2 present in the system. The products of the reaction were found to be COS and SO2 with one molecule of each being formed for every reacted CS2. A value of (2.7 ± 0.6) × 10−12 cm3/molecule·s was obtained as effective rate constant for the reaction at 293 K in 760 torr of synthetic air.
68 citations
TL;DR: In this paper, a hydrogen bonding type of interaction between the carbonyl bond of PCL and the α-hydrogen of PVC was found in compatible PCL-PVC blends.
Abstract: FT-IR spectroscopic studies have been performed in an attempt to elucidate the nature of the specific interactions occurring in miscible poly(ϵ-caprolactone) (PCL)-poly (vinyl chloride) (PVC) blends. Studies of low molecular weight analogues, polymer/solvent mixtures and blends of PCL and α-deuterated PVC are presented. The results strongly suggest that a hydrogen bonding type of interaction between the carbonyl bond of PCL and the α-hydrogen of PVC exists in compatible PCL-PVC blends.
67 citations
TL;DR: In this article, a bakeable high-vacuum cell based on a modification of a commercial diffuse reflectance infrared cell is described along with means for controlling the gaseous and thermal environment.
Abstract: Measurement of the reaction of water vapor and carbon dioxide with lithium compounds such as LiH and LiOH has been carried out in situ using diffuse reflectance infrared Fourier transform (DRIFT) Spectroscopy. The bakeable high-vacuum cell, based on a modification of a commercial diffuse reflectance infrared cell is described along with means for controlling the gaseous and thermal environment.
TL;DR: In this paper, the use of a high-resolution Fourier transform spectrometer was used to analyse the laser-induced fluorescence from a ring dye laser, which allowed the first time of the first use of such a high resolution Fourier Transform Spectrometer.
TL;DR: The maximum entropy method (MEM) is applied to the interferogram data obtained using the technique of Fourier transform spectroscopy for estimating its spectrum with a resolution far exceeding the value set by the spectrometer.
Abstract: The maximum entropy method (MEM) is applied to the interferogram data obtained using the technique of Fourier transform spectroscopy for estimating its spectrum with a resolution far exceeding the value set by the spectrometer. For emission line data, the MEM process is directly used with the interferogram data in place of the regular Fourier transformation process required in Fourier transform spectroscopy. It produces a spectral estimate with an enhanced resolution. For absorption data with a broad background spectrum, the method is applied to a modified interferogram which corresponds to the Fourier transform of the absorptance spectrum. Two results are presented to demonstrate the power of the technique: for the visible emission spectrum of a spectral, calibration lamp and for the infrared chloroform absorption spectrum. Included in the paper is a discussion of the problems associated with practical use of the MEM.
TL;DR: In this article, the vibrational spectrum associated with hydrogen chemisorbed on Si(100) was studied for the first time by means of Fourier transform infrared spectroscopy, and the effective charge, e * /e=0.01, was consistent with early theoretical predictions.
IBM1
TL;DR: In this paper, a switching circuit was incorporated into the data acquisition electronics of an air-equilibrated IBM IR/98 FTIR Spectrometer such that it is possible to obtain simultaneously both reference and polarization modulated spectrum.
TL;DR: The infrared spectrum of the complex of D-fructose 1,6-bisphosphate bound to yeast aldolase displays three spectral features between 1700 and 1800 cm-1 that probably corresponds to an enzymic carboxyl group in a nonpolar environment.
Abstract: The infrared spectrum of the complex of D-fructose 1,6-bisphosphate bound to yeast aldolase displays three spectral features between 1700 and 1800 cm-1. One of these (at 1730 cm-1) corresponds to the carbonyl group of enzyme-bound D-fructose 1,6-bisphosphate and/or dihydroxyacetone phosphate. The frequency of this band, which is unaffected by the removal of the intrinsic zinc ion from the enzyme, demonstrates that this carbonyl group is not significantly polarized when the substrate binds to the enzyme. In contrast, the spectral band assigned to the carbonyl group of enzyme-bound D-glyceraldehyde 3-phosphate (at 1706 cm-1) appears at a frequency 24 cm-1 lower than when this substrate is in aqueous solution. This shift indicates considerable polarization of the carbonyl group when D-glyceraldehyde 3-phosphate is bound at the active site. The third spectral feature (at 1748 cm-1), which is observed only in the presence of potassium ion, probably corresponds to an enzymic carboxyl group in a nonpolar environment.
TL;DR: In this paper, the feasibility of micro-bore HPLC/FTIR has been shown, which will enable chromatographers to economically use exotic solvents with large infrared windows.
Abstract: Results which have evolved from an evaluation of high performance liquid chromatography/Fourier transform infrared spectrometry (HPLC/FTIR) employing semipreparative, analytical, and microbore scale separations are presented. Normal-phase chromatography on silica gel has been carried out with Freon-113 elution. Model mixtures of aliphatic and aromatic hydrocarbons and nonpolar constituents in coal liquefaction process solvents have been separated. Best results have been obtained with the semipreparative and microbore modes because of the higher sample concentration developed at the detector. This study has shown the feasibility of microbore HPLC/FTIR which will enable chromatographers to economically use exotic solvents with large infrared windows.
TL;DR: In this paper, the infrared absorption bands of acetylene dimers have been investigated with long path low temperature Fourier transform infrared spectroscopy, and five bands were found, three of (HCCH)2 and two of (DCCD)2.
Abstract: The infrared absorption bands of acetylene dimers have been investigated with long path low temperature Fourier transform infrared spectroscopy. Five bands were found, three of (HCCH)2 and two of (DCCD)2. Four of these bands can be assigned as coupled monomer modes. Normal mode analysis based on a theoretical intermolecular potential confirms these assignments. One band shows evidence of fast vibrational predissociation, and a symmetry based argument is made to support the claim that the predissociation fragments are rotationally excited.
TL;DR: In this paper, the high-resolution infrared spectrum of N 2 O in the region of ν 2 has been studied with a Fourier transform spectrometer at a resolution of (about) 0.005 cm −1 and an accuracy of about ± 0.00005 cm − 1.
TL;DR: In this paper, the authors used Fourier transform infrared spectroscopy and solid state 13C NMR spectroglobalization to measure the hydroxyl groups in coal and found that the proportion of phenolic to alkyl OH is approximately constant for the coals used in this study.
Abstract: Fourier transform infrared spectroscopy and solid state 13C NMR spectroscopy have been used to measure the hydroxyl groups in coal. The methodology depends upon measuring the intensities of bands and resonances assigned to the products of acetylation reactions. In the infrared three separate bands, assigned to acetylated phenolic OH, alkyl OH, and NH groups, can be identified. In NMR, we used the methoxy carbon to determine the total OH. Spectroscopic measurements demonstrate that not only does the total OH content of coals but also the individual types of OH groups vary systematically as a function of rank. The proportion of phenolic to alkyl OH is approximately constant for the coals used in this study.
TL;DR: In this article, the infrared absorption spectrum of formamide (HCONH2 or DCONH2) at room temperature was recorded using Fourier transform infrared (FTIR) spectrophotometry.
Abstract: Taking advantage of the Fourier transform infrared (FTIR) spectrophotometry in accumulating a very weak available radiation, which comes out from a multiple-reflection-type gas-cell (17 m), we have been able to record the infrared absorption spectrum of formamide (HCONH2 or DCONH2) at room temperature, where its vapor pressure is only 0.1 Torr (1 Torr≈133.322 Pa) in the order of magnitude. From an analysis of the rotational structure (resolution 0.5 cm−1) of the C–H stretching band, a revised set of parameters has been obtained. A Q-branch analysis was made for the v=2←0 and v=3←1 bands (resolution 0.24 cm−1) of the amino wagging vibration, where v is its vibrational quantum number. The rotational constants A−B were determined to be 2.0269 cm−1 for the v=2 state and 1.9990 cm−1 for the v=3 state, and the transition frequencies 657.75 cm−1 for v=2←0 and 769.85 cm−1 for v=3←1. On the basis of these new parameter values, a discussion was made of the amino wagging coordinate of this molecule.
TL;DR: In this paper, the structures of glasses prepared by melting mixtures of alkali borosilicate glass and silicon nitride powders were studied using Fourier transform infrared spectroscopy and combustion analysis.
Abstract: The structures of glasses prepared by melting mixtures of alkali borosilicate glass and silicon nitride powders and by ammonolysis of porous borosilicate gels were studied using Fourier transform infrared spectroscopy and combustion analysis. Whereas there was little evidence of nitride bond formation in the melt prepared glasses, SiN and BN bonding were observed in the gel-derived glasses. It is proposed that these differences occur because Na2O and B2O3 are reduced by Si3N4 in the melt to form SiO2 + N2 + metal. In comparison, ammonolysis of gels is a low temperature process (
TL;DR: Spectra suggest that adriamycin could be interacting also with the proteins of the membrane within intercalating process of treated tumor cells.
TL;DR: The rates of solid-solid phase transitions have been measured by nonspectroscopic techniques, such as differential thermal analysis (DTA), dilatometry, and x-ray powder diffraction as discussed by the authors.
Abstract: The rates of solid-solid phase transitions have been measured by nonspectroscopic techniques, such as differential thermal analysis (DTA), dilatometry, and x-ray powder diffraction. With DTA, the accuracy of the activation energy is rarely better than ±15% in part because good thermal contact between the sample and, the pan is difficult to maintain. Dilatometry measures the volume change accompanying a thermodynamic first order phase transition. Crystal decomposition and out-gassing of trapped solvent molecules complicate the method. High temperature x-ray powder diffraction is restricted to relatively slow phase transformations. If the solid phase transition is quenched and the intensity of a characteristic peak measured, errors can be incurred in determining the concentration. Internal standards may alleviate this problem, but sample homogeneity becomes an issue.
TL;DR: SIESLER et al. as discussed by the authors demonstrated the potential of this technique applied to NH-deuterated specimens of these polyester urethanes with reference to a more detailed insight into phase separation and the orientation mechanism of the phase-separated hard segments during uniaxial elongation and recovery.
Abstract: In the preceding papers of this study (SIESLER 1983, 1983a) the results of rheo-optical FTIR investigations at ambient and elevated temperature obtained from a series of model polyester urethanes with varying composition have been discussed in terms of the phase separation and segmental orientation of these polymers. The present work demonstrates the potential of this technique applied to NH-deuterated specimens of these polyester urethanes with reference to a more detailed insight into phase separation and the orientation mechanism of the phase-separated hard segments during uniaxial elongation and recovery.
IBM1
TL;DR: Good chromatographic resolution, low nanogram sensitivity, and compound identification are demonstrated and applications to the analysis of a petroleum distillation fraction and to a polymer sample, analyzed after pyrolysis, are presented.
Abstract: In this work, we describe the interfacing of a high-resolution chromatographic system featuring narrow bore gas chromatographic columns to a Fourier transform infrared spectrometer. Excellent chromatographic resolution, low nanogram sensitivity, and compound identification are demonstrated. Applications to the analysis of a petroleum distillation fraction and to a polymer sample, analyzed after pyrolysis, are presented. A vapor-phase library search system is used to identify compounds in both samples.
TL;DR: In this article, Fourier transform infrared spectrometry (FTIR) has been used as a detector for microbore high-performance liquid chromatography (HPLC) through the use of a low volume transmission flow cell.
Abstract: Fourier transform infrared spectrometry (FTIR) has been used as a detector for microbore high-performance liquid chromatography (HPLC) through the use of a low volume transmission flow cell. Characteristics of the system have been determined and compared with analytical scale HPLC separations with FTIR detection. Improvement in sensitivity is reported for the microbore scale system over the analytical scale system. Direct comparison of the detection limits considering equal quantities injected for 2,6-di-tert-butylphenol is made for both systems. 9 figures, 1 table.